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    <meta charset="UTF-8">
    <title>Document</title>
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<body>
    <script>
      var a = 1.523154562;
      console.log(a.toFixed(3));

      var str = 'abcdefghijklmn';
      console.log(str.charAt(5));
      console.log(str.indexOf("d"));
      console.log(str.lastIndexOf("d"));
      console.log(str.split(','));
      console.log(str.substr(2,3));
      console.log(str.substring(4,6));
      console.log(str.toLowerCase());
      console.log(str.toUpperCase());

      var arr = [2,2,3,5,'a','f','r'];
      var arr2 = [7,8,9,6,'c','b','h'];
      console.log(arr.length);
      console.log(arr.concat(arr2));
      console.log(arr.join('-'));
      console.log(arr.pop());
      console.log(arr.push(8,6));
      console.log(arr.reverse());
      console.log(arr.shift());
      console.log(arr.sort());
      console.log(arr.unshift(2,8,9));
      console.log(arr.slice(2,5));
      console.log(arr.splice(3,7));

      console.log(Math.abs(-8.4));
      console.log(Math.ceil(4.1));
      console.log(Math.floor(4.9));
      console.log(Math.max(3,5,6));
      console.log(Math.min(3,5,3));
      console.log(Math.pow(3,5));
      console.log(Math.random());
      console.log(Math.round(2.5));

    </script>
</body>
</html>